1. Field of the Invention
Embodiments disclosed herein may be directed to a sensor for detecting a fluid leak, specifically an optical sensor which detects a leak based on transmittance properties of the fluid. In particular, embodiments disclosed herein may be directed to an optical leak detection sensor for detecting a leak in a flow cell battery system.
2. Description of the Relevant Art
Reduction-oxidation (redox) flow batteries store electrical energy in a chemical form, and subsequently dispense the stored energy in an electrical form via a spontaneous reverse redox reaction. A redox flow battery is an electrochemical storage device in which an electrolyte containing one or more dissolved electro-active species flows through a reactor cell where chemical energy is converted to electrical energy. Conversely, the discharged electrolyte can be flowed through a reactor cell such that electrical energy is converted to chemical energy. Electrolyte solution is stored externally, for example in tanks, and flowed through a set of cells where the electrochemical reaction takes place. The electrolyte tanks and cells may often be stored in a housing, which offers protection for the electrolyte tanks and cells. Externally stored electrolytes can be flowed through the battery system by pumping, gravity feed, or by any other method of moving fluid through the system. The reaction in a flow battery is reversible. The electrolyte, then, can be recharged without replacing the electroactive material. The energy capacity of a redox flow battery, therefore, is related to the total electrolyte volume, e.g., the size of the storage tank. However, the electrolytes in the system and stored in the tank may be corrosive to the housing and other components of the battery, and possibly even harmful to people and the environment, if leaked to the exterior of the housing. Accordingly, it is important to monitor the components of the flow battery system for electrolyte leakage.
Many leakage sensors used in batteries and other environments to detect a leak of a hazardous or corrosive fluid, will detect the presence of a fluid and then provide an indication that there is a leak. However, in many instances, the fluid being detected is not indicative of a leak. Rather, the fluid may be ambient or environmental fluid, such as rain water. When a leakage sensor indicates a leak due to a fluid such as rain water, it takes time for a person to investigate the so-called leak, and determine that there is not, in fact, a leak. Accordingly, it is important to not only monitor the components of a flow battery system for electrolyte leakage, but also to discern between electrolyte solution and other fluids.